PRESERVATION OF ELEMENTAL AND ISOTOPIC SOURCE IDENTIFICATION OF SEDIMENTARY ORGANIC-MATTER

The amount and type of organic matter in the sediments of lakes and oceans contribute to their paleoenvironmental and paleoclimatological records. Only a small fraction of the initial aquatic organic matter survives destruction and alteration during sinking and sedimentation. Selective degradation modifies the character of the surviving small fraction of organic matter which becomes incorporated in bottom sediments. Organic matter alterations can continue to sub-bottom depths of hundreds of meters, corresponding to millions of years. Source and paleoenvironmental information nonetheless remains preserved in the molecular, elemental and isotopic compositions of organic matter. C/N- and deltaC-13-values of total organic matter, in particular, appear to retain paleoenvironmental information for multi-Myr time periods.